The present invention relates generally to spiral magnets. More specifically, the present invention relates to devices comprising spiral magnets which are usefully employed for therapeutic applications.
The use of magnetic fields for therapeutic application is well known. For example, U.S. Pat. No. 4,549,532 to Baermann (the entire content of which is expessly incorporated hereinto by reference) discloses a flexible magnetic foil for therapeutic purposes. Primarily, the therapeutic action is produced by the Hall effect, which causes a load separation within an electrolyte which flows through the magnetic field. Electric voltages are thereby created diagonally to the flow direction, which can generate the desired therapeutic action in the sections of the body thus treated.
Such devices for therapeutic application are typically manufactured using foils made of a rubber-type flexible plastic, which is preferably skin-compatible. Permanently magnetic particles are embedded in the plastic, which are preferably permanently magnetic particles of a ferrite or rare-earth component, for example such as barium or strontium ferrite, or NdFeB. These permanently magnetic particles are aligned by applying an external magnetic field to one, or both, side(s) of the foil and thus create a magnetically polarized area. The conventional foil is thus a sheet-type formation, with a commonly available foil thickness of between 0.3 mm and 1.5 mm.
Various designs of such conventional magnetic foils are known. They are made by stamping or cutting from commonly available magnetic foils, normally in the form of circular discs or rectangles. Double or multi-polar magnetization is usually carried out laterally on one side. The pole configurations thereby are usually in the form of straight lines, concentric circles, spirals, rectangles, or sections, as well as other geometric formations. Only in the case of axial magnetization, whereby one surface has a single N-pole and the reverse side of the foil a single S-pole, are identical magnetic induction values shown at corresponding measuring points on both sides.
In contrast to a double sided lateral multi-polar magnetization, the afore-mentioned single-sided lateral multi-polar magnetization has the advantage that it is normally very practical and shows higher induction values on the side of the foil adjacent to the patient""s body than it would exhibit in the case of two-sided lateral polarization with the identical pole configuration, irrespective of the configuration.
However, the above dual or multi-polar lateral magnetizations of such sheet-type formations are unfavorable due to the magnetic flux direction being curved within large sections of the foil. The desired total saturation polarization of the overall available magnetic material, on the utilization side of the foil facing the body, can thus no longer be ensured.
This problem proves to be of particular disadvantage for magnetic foils used for therapeutic purposes, where the pole width is larger than the foil thickness. However, magnetizing with pole widths which are in excess of the 1-time, often even 20-times, that of the foil thickness are preferred due to their desired greater dispersion into deeper areas of the body. An additional disadvantage of this type of magnetization has proven to be the leakage flux which forms on the reverse side of the foil, due to the low relative permeability of xcexcr=1.0. This may be as much as 75% of the area of the foil facing the body and reduces the desired beneficial flow considerably.
In some cases however, this disadvantage is compensated by the side of the foil facing the body being covered by a magnetic, highly permeable foil, for example of thin low-carbon steel sheeting. Due to this magnetic reflux, the utilization flux of the foil is highly increased. A disadvantage however, is the use of steel sheeting which, due to its negligible thickness, presents a considerable injury potential. Its use increases the manufacturing price and also reduces the flexibility of the foil.
Therefore, in summary, the use of such magnetic therapeutic devices is limited by the strength of the polarization. With a weak polarization of the foil used, the effect produced by the magnetic field within the body, is also weak.
The present invention is based on the purpose of providing a magnetic device for therapeutic application which may be easily manufactured and which generates a strong and effective magnetic field.
By this invention, the above purpose is accomplished by a magnet spiral for therapeutic application with minimum one foil strip made of a rubber-type flexible, preferably skin compatible, plastic which is coiled up along its lengthwise dimension in form of a spiral, whereby the foil strip is magnetically polarized in an axial direction relative to its larger lateral face (i.e. in its lengthwise direction).
Preferably, the magnet spiral according to the present invention includes a minimum of one magnetically polarized foil strip which is coiled up into a spiral. Thereby, the larger lateral faces of the foil are magnetically polarized in an axial direction of the foilxe2x80x94that is, in the lengthwise direction of the foil strip, preferably up to its total saturation. The axial direction refers to the foil in its coiled condition. In the coiled condition of the foil, one side of the larger lateral area thus faces the other large lateral area. Starting at the center this configuration creates in a radial direction a sequence of varying magnetic polarizations within the cross section of the magnet spiral. The effect of this series arrangement of the magnetic polarizations causes the creation of a particularly strong magnetic field in the vicinity of the magnet spiral. The strength of the magnetic field is caused in particular by a multitude of magnetic dipoles being arranged in series along their magnetic axes.
In the case of the magnet spiral according to the present invention, the foil strip may be coiled up around itself, or around an object of optional form in the center of the spiral. The magnet spiral of the present invention invention may, for example, have a largely circular form circumference, or a rectangular periphery with rounded-off corners, or irregularly shaped.
In preferred embodiments, the foil has the form of an enlongated strip with right angled cross section, whereby powder-type magnetic components, preferably Sr-ferrite or NdFeB of particle size smaller than 1 mm, particularly preferable smaller than 100xcexc, are embedded in as evenly formed statistical dispersion as possible. In the case of such a strip, the larger lateral faces are those faces, which run in the longitudinal direction of the strip and which are broader. A strip-type foil is particularly easy to coil. For the manufacture of a magnet spiral according to the present invention, it is useful for the practical application to positionally fix the free end of the strip, in the coiled-up condition, to the magnet spiral. This may be achieved, for example, by using an adhesive strip or a similar fixing method.
In another preferred embodiment of the invention, a minimum of two different polarizations are applied to each of the large lateral faces, whereby the polarization is in each case set in opposition. Thereby, beside the magnetic effect caused by the axial polarization of the foil, a further source for the magnetic field is created due to the additional magnetic polarization on the larger lateral face, which acts similarly to a dipole arranged across the axial direction of the foil. The field distribution of the magnet spiral can thereby be favorably modified.
Several areas of varying polarization may follow on the one side, along the lengthwise extent of the foil""s coil. With a series arrangement of varying polarization areas on the one side, along the lengthwise direction, two areas of identical polarization become adjacent to one another in one section of the coiled foil. Whereas, in the case of identical polarization of the large side areas, two varying polarizations always abutt, so that in the cross-section of the magnet spiral North pole and South pole of a dipole always abutt. In the case of a different polarization on the large side areas, a North pole of one foil sectionxe2x80x94in the cross-section of the magnet spiralxe2x80x94abutts at least once to a North pole of another following foil element, lying in the winding direction. With reference to the magnetization of the spiral, three ring shaped poles of the magnet spiral are created in the area in which, for example, two regions of identical polarization meet. When such a meeting of identical polarization occurs, the magnet spiral largely shows a rotation symmetric polarization which occurs in radial direction, for example with a North-pole, South-pole and North pole again. The pole sequence is caused by two foil elements for example, being aligned contrary to one another, whereby North-pole abutts North-pole. Such a magnetic field, with more poles, may also be favorable for therapeutic application, since the change of the magnetic fields has additional and particularly favored effect on electrolytes in the vicinity of the field.
In one useful form, the areas following one another in the longitudional direction of the foil""s winding, represent a length of a minimum angle zone of 2xcfx80 radians each. Thereby it is ensured that a fundamental rotation-symmetric field distribution is created.
Preferably the spiral is in the form of an essentially cylindrical configuration, with the cylinder height being smaller than the cylinder diameter. A magnet spiral so dimensioned is easy to handle.
The objective of the invention is also accomplished by a device for therapeutic application, particularly a bandage, pocket and face mask, which contains at minimum one of the above described spirals. A minimum of one foil, coiled up into a spiral, is arranged in a device for therapeutic application. Therefore, bandages, pockets and face masks are suitable. The device is worn with its effective surface as close as possible to the body part which is intended to be treated and is in need of the magnetic therapy.
In a further embodiment of the invention, a minimum of two foils, each coiled in the shape of a spiral and set with a space between them is intended. Thereby, similar to a Helmholtz coil pair, a magnetic field can be created between the two spirals. Such a magnetic field may be particularly favourable for a therapeutic application of the device. Also, the individual foils coiled into spirals may be arranged in the device in such a way that very specific field configurations are created, insofar as this is desired for a therapeutic action.
In a preferred implementation of the invention, a minimum of two foils, each coiled in the shape of a frontal spiral, are intended to be arranged essentially with spiral axes falling on top of one another, with a space between them . Thereby, for example, a minimum of two alternating magnetic poles are created, between which the part of the body to be treated may be arranged.
Favourably, the front of the spiral is arranged in the vicinity of the body part to be treated. An advantage of such a spiral arrangement is that there is a very strong magnetic field along the effective area of the device. Therefore for example, the spiral may be arranged inside a bandage or a pocket parallel to the skin.
These and other aspects and advantages will become more apparent after careful consideration is given to the following detailed description of the preferred exemplary embodiments thereof.